Magnetic disk coatings

Abstract

A magnetic disk coating composition contains magnetic particles and a binder system comprising epoxy and phenolic resins, a titanate coupling agent and a water miscible solvent system, the coating having a pigment volume concentration of up to 35.

We claim: 
     
       1. A mixture for coating a magnetic recording member to produce a magnetic coating having magnetic particles in a binder system in a pigment volume concentration of up to 35, where pigment volume concentration is defined as the ratio of the volume of said magnetic particles to the sum of the volume of said binder system and the volume of said magnetic particles, comprising said binder system including a water-miscible solvent system comprising glycol ethyl ether, hydroxyethylacetate and diethyleneglycolbutylether,   an epoxy resin selected from a group of epoxy resins which are soluble in each component of said water-miscible solvent system,   a phenolic resin selected from a group of phenolic resins which are soluble in each component of said water-miscible solvent system, and   a titanate coupling agent for improving the bond of said magnetic particles to said resins and for catalyzing the cross-linking of said resins,   each of said components of said water-miscible solvent system being compatible with said titanate coupling agent.     
     
     
       2. A mixture in accordance with claim 1, in which said binder system includes at least one flow additive material.   
     
     
       3. A mixture in accordance with claim 1, in which the ingredients are present in said mixture in the following range of proportions:   ______________________________________                                    
Ingredient       Parts (Weight/weight)                                    
______________________________________                                    
Epoxy Resin      20-26                                                    
Phenolic Resin   40-52                                                    
Titanate Coupling Agent                                                   
                 0.5-2.0                                                  
Water Miscible Solvents                                                   
                 150-190                                                  
Magnetic Particles                                                        
                  80-110                                                  
______________________________________                                    
     
     
     
       4. A mixture in accordance with claim 1, in which the ingredients are present in said mixture in the following proportions:   ______________________________________                                    
Ingredient       Parts (Weight/weight)                                    
______________________________________                                    
Epoxy Resin      24                                                       
Phenolic Resin   48                                                       
Titanate Coupling Agent                                                   
                 1.4                                                      
Water Miscible Solvents                                                   
                 174                                                      
Magnetic Particles                                                        
                 95                                                       
______________________________________                                    
     
     
     
       5. A mixture in accordance with claim 3, including at least one flow additive material present in a range from 3 to 7 parts weight/weight. 
     
     
       6. A mixture in accordance with claim 1, including at least one flow additive material present in an amount of 5 parts weight/weight.